The present invention relates to IC test equipment of the type wherein IC elements to be tested are carried by a horizontal carrier mechanism to testing stations.
FIG. 1 shows an IC transport mechanism of IC test equipment employing a conventional horizontal transport system.
An X-Y carrier head 1H has air chucks 3A and 3B. The X-Y carrier head 1H picks up IC elements 4 by the air chucks and travels to a desired position, where the IC elements 4 are placed on sockets 5A and 5B provided on a performance board PB on a test head TH and then are subjected to a test. After the test the X-Y carrier head 1H lifts up the IC elements 4 from the sockets 5A and 5B and brings them to a predetermined position. The X-Y carrier head 1H is provided with vertical guides 6A and 6B for supporting the air chucks 3A and 3B in a manner to be movable in the vertical direction and vertical drivers 7A and 7B for moving the air chucks 3A and 3B in the vertical direction. The vertical drivers 7A and 7B are, for example, air cylinders or similar drivers.
The vertical drivers 7A and 7B not only move the air chucks 3A and 3B in the vertical direction but also urge them against the sockets 5A and 5B on the performance board PB, i.e. press terminal portions of the IC elements 4 into contact with terminals of the sockets 5A and 5B to ensure establishment of electrical contact therebetween. The pressure needed in this case is about 30 kg per IC element 4. Accordingly, cylinders each capable of producing a driving force of 30 kg or so are used as the vertical drivers 7A and 7B for urging the two IC elements 4 into contact with the sockets 5A and 5B as shown.
Such a large driving force is not needed for only moving up and down the air chucks 3A and 3B, but the driving force is necessary for bringing the IC elements 4 into electrical contact with the sockets 5A and 5B and maintaining the contact during the test. A large and consequently heavy air cylinder is required for generating such a large driving force. This inevitably increases the total weight of the X-Y carrier head 1H. In addition, when the IC elements 4 are being urged against the sockets 5A and 5B, the X-Y carrier head 1H is subjected to an upward reaction force of 30.times.2 kg. Consequently, a reaction force of about 60 kg is also applied to a Y-axis guide rail 1Y supporting the X-Y carrier head 1H; accordingly, it is necessary that the whole structure of an X-Y transport unit 10 be also rigid enough to withstand the reaction force.
As a result of this, however, the weight of the X-Y carrier head 1H itself and consequently the total weight of the X-Y transport unit 10 increases--this hinders speedup of operations of the X-Y carrier head and hence constitutes a serious obstacle to the reduction of the test time.